This disclosure relates generally to equipment utilized and operations performed in conjunction with a subterranean well and, in an example described below, more particularly provides for injection of fluid into one or more selected zones in a well, and provides for magnetic field sensing actuation of well tools. It can be beneficial in some circumstances to individually, or at least selectively, actuate one or more well tools in a well. Improvements are continuously needed in the art which may be useful in operations such as selectively injecting fluid into formation zones, selectively producing from multiple zones, actuating various types of well tools, etc.